如果项目没有日期，则不显示任何内容

Question

如果没有日期，我希望我的代码不显示任何内容。

这是我的代码：

#include <stdio.h>
#include <stdlib.h>

struct node{
    int num;
    struct node *next;
};
//Make the struct

typedef struct {
    struct node * first;
    struct node * current;
}linkedList;

void addNode(linkedList* list, int a);
void addFirstNode(linkedList* list, int b);
//Function prototypes

int main() {

    linkedList *list = (struct node *)malloc(sizeof(struct node));;
    addFirstNode(list, 1);
    addNode(list, 2);
    addNode(list, 3);
    addNode(list, 4);
    addNode(list, 5);
    addNode(list, 6);
    addNode(list, 7);
}

void addFirstNode(linkedList* list, int input) {

    list->first = (struct node *)malloc(sizeof(struct node));   //Make first node
    list->first->num = input;                                 //Fill first node
    list->current = list->first;
}
void addNode(linkedList *list, int input) {

    struct node * newNode = (struct node *)malloc(sizeof(struct node));
    newNode->num = input;
    list->current->next = newNode;    //Segmentation fault! (core dumped)
    list->current = newNode;
}

因为我将其格式化为=format(IIF(Fields!Phase.Value = "Pre-Feasibility" OR Fields!Phase.Value = "Selection", Fields!PreFeasibilityCurrentTargetDate.Value, IIF(Fields!Phase.Value = "Feasibility" OR Fields!Phase.Value = "Definition", Fields!FeasibilityCurrentTargetDate.Value, IIF(Fields!Phase.Value = "Implementation", Fields!ImplementationCurrentTargetDate.Value, ""))), "dd-MMM-yy") ，所以当项目没有日期时会显示。如果它没有日期，我怎么能改变它以显示任何内容。

Answer 1

将表达式的空白值更改为空

=Iif(Fields!Phase.Value="Operation","-", format(
IIF(Fields!Phase.Value = "Pre-Feasibility" OR Fields!Phase.Value = "Selection", 
   Fields!PreFeasibilityCurrentTargetDate.Value, 
   IIF(Fields!Phase.Value = "Feasibility" OR Fields!Phase.Value = "Definition", 
      Fields!FeasibilityCurrentTargetDate.Value, 
      IIF(Fields!Phase.Value = "Implementation",
        Fields!ImplementationCurrentTargetDate.Value, Nothing)))
, "dd-MMM-yy") )

我还建议您使用字段格式属性而不是值表达式中的格式函数。在这种情况下，即使字段值为空白也可以使用

Answer 2

在这里查看MSDN表单， https://msdn.microsoft.com/en-us/library/ms157406.aspx

它清楚地提到“如果指定了无效的格式字符串，则格式化的文本将被解释为覆盖格式的文字字符串。”

因此。您需要在格式化后检查字符串，

IIF(output="dd-MMM-yy","",output)